Distributed Detection Inverters for On-Chip Light Attack Sensing
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Solution Overview
Problem
Existing semiconductor integrated circuits face challenges in detecting local laser light irradiation for security microcomputers due to large photodetector element sizes and limited detection sensitivity, which can lead to malfunctions and data breaches.
Innovation Solution
The implementation of series-coupled detection inverters with a CMOS inverter structure, where a leak current is generated at reverse-biased pn junctions, enhancing detection sensitivity and reducing the required chip area for light irradiation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photodetector elements having an npnp thyristor structure are used, then detection sensitivity to light irradiation is improved, but the size of each photodetector element becomes large, causing constraint on layout design arrangement in terms of area dimensions
Solution Approach 1:
The patent changes the structural parameters of the photodetector element by using a simple reverse-biased pn junction instead of a complex npnp thyristor structure. This parameter change maintains detection sensitivity while significantly reducing the area occupied by each photodetector element on the chip.
Solution Approach 2:
The patent extracts only the essential functional component (the pn junction) needed for light detection, removing unnecessary complex structures like the npnp thyristor. This extraction achieves the detection function with minimal area occupation.
2Reliability
If an output terminal of each photodetector element is coupled to each of a plurality of MOS transistors, then detection capability is improved, but it is required to provide a plurality of MOS transistors for each photodetector element, thereby imposing constraint on photodetector element layout design arrangement in terms of area dimensions
Solution Approach 1:
The patent merges multiple photodetector elements into a single integrated detection unit where multiple reverse-biased pn junctions share common terminals. This merging reduces the total number of separate components (MOS transistors) needed while maintaining the ability to detect light irradiation across multiple locations.
Solution Approach 2:
The patent creates a universal detection structure where a single photodetector element with multiple pn junctions can detect light irradiation at multiple locations simultaneously. This multi-functional design eliminates the need for separate MOS transistors for each detection point, reducing overall chip area.
3Measurement precision
If a multiplicity of photodetector elements are mounted on a chip for detection of local laser light irradiation, then detection coverage is improved, but it is desired to provide small-sized photodetector elements having excellent sensitivity of detection
Solution Approach 1:
The patent applies local quality by distributing multiple small reverse-biased pn junction photodetector elements across different locations on the chip. Each local photodetector provides detection sensitivity while the distributed arrangement ensures comprehensive coverage against localized laser light irradiation attacks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for high detection sensitivity to local light irradiation on a small chip occupancy area, effectively preventing malfunctions and ensuring reliable security against fault-based attacks.
Implementation Method 1
a leak current is generated at reverse-biased pn junctions
Data Source
AI summary
An arrangement for detecting local light irradiation in an illegal attack attempt to intentionally induce a malfunction or faulty condition is formed on a small chip occupancy area so as to provide high detection sensitivity. In a region containing a logic circuit, a plurality of series-coupled detection inverters are distributively disposed as photodetector elements having a constant logical value of primary-stage input. When at least one of the series-coupled detection inverters is irradiated with light, an output thereof is inverted, thereby producing a final output through the series-coupled detection inverters. Based on the final output thus produced, local light irradiation can be detected.